Question 1112673
Expect 30 days of work at Rs 120 per day;
expect to lose Rs 30 per day of skipped work;
Amount Earnings Rs 2700


If worked all 30 day, then  {{{30*120=3600}}} of Rs units.
If work is skipped, the skipping REMOVES Rs 30 from any that has been earned.


n, number of days not work (for the penalty Rs 30)
y, number of days did work (for earning)
{{{120y-30n=2700}}}
-
{{{4y-n=90}}}
-
total number of days for possible work in the period, 30;
{{{y+n=30}}}


{{{system(4y-n=90,y+n=30)}}}


Question asks for n, so ...
{{{system(4y-n=90,4y+4n=120)}}}
{{{E2-E1}}}

{{{5n=30}}}

{{{highlight(highlight(n=6))}}}